Question

One mole of an ideal monoatomic gas is heated at a constant pressure of one atmosphere from $0^{\circ }$ to ${100}^{\circ }C$ then the change in the internal energy is

• A. $6.56joules$
• B. $8.32\times {10}^{2}joules$
• C. $12.48\times {10}^{2}joules$
• D. $20.80joules$

Answer 1

The correct option is C $12.48\times {10}^{2}joules$

Change in internal energy is always equal to the heat supplied at constant volume i.e.
$△U=(q{)}_v=n{C}_v△T$
$△T=373-273=100K$
for monoatomic gas $C_v=\frac{3}{2}R$
$△U=n\left(\frac{3}{2}R\right)△T=1\times \frac{3}{2}\times 8.31\times 100=12.48\times {10}^{2}J$